Just recently, the bathtub in the main bathroom can only get warm or hot water. With the faucet in the cold water position, the water is bathwater warm, getting steadily hotter as the faucet is moved in the hot water direction. All the other faucets in the home work okay, including the sink in that same bathroom, and we've made no changes. What could cause this?

What kind / brand / type of faucet is it ? Please provide more detailed information. Back to you. Milo

It is the 2004 version of the Moen Banbury Single Handle Tub and Shower faucet.